Chrome Version: 61.0.3123.0 (Official Build) canary (64-bit)
OS: macOS

What steps will reproduce the problem?
(1) Load Gmail
(2) Click "+" to attempt to start a Hangouts chat with someone

What is the expected result?

Expect to be able to search for someone's name.

What happens instead?

Layout's completely broken. It looks like the entire Hangouts chat panel shows up inside the pop-up.

If you need a screenshot let me know and I'll put one on Google Drive. It would contain PII so I'm not attaching it to this bug report.